New and everlasting covenant of marriage

Marriage performed under the law of the gospel and the holy priesthood is for mortal life and for eternity. Worthy men and women thus sealed in the temple in marriage may continue as husband and wife throughout eternity.

Plural marriage

The marriage of a husband to two or more living wives. It is lawful for a man to have only one wife, unless the Lord commands otherwise by revelation (Jacob 2:27–30). By revelation, plural marriage was practiced in Old Testament times and in the early days of the restored Church by the direction of the prophet who held the priesthood keys (D&C 132:34–40, 45). It is no longer practiced in the Church (D&C OD—1); today, having more than one wife is incompatible with membership in The Church of Jesus Christ of Latter-day Saints.